It is known that vitamin D.sub.3 or its derivative is related with the calcium metabolism, or intestinal calcium absorption, dissolution of bone salts in the bone tissues and bone formation of warm-blooded animals and is expected to be used as a remedy or a preventive for diseases resulting from anormal calcium metabolism such as renal ostes dystrophy, parathyroid insufficiency, osteoporosis, osteomalacia, syndrom of absorption disturbances, etc. However, vitamin D.sub.3 or its derivative presents a problem that its excess dosage causes a seriously harmful subsidiary effects since it also has a function of dissolving the bone salts. Expectations may therefore be held that vitamin D.sub.3 or its derivative can be used as a bone formation stimulant with greater safety, if only the function of dissolving the bone salts can be depressed among the functions of vitamin D.sub.3 or its derivative while such functions as the promotion of the absorption of calcium from the intestinal tract and the stimulation of ossifying function in the bone tissue are well preserved.
The present inventors, having conducted a research on the bone salt dissolving function of 1.alpha.-hydroxycholecalciferol, one of the derivatives of vitamin D.sub.3, came to know and already made it public (at the general meeting held by the Japanese Pharmacological Society on Mar. 25, 1978, at Sendai) a fact that, after a series of tests with the use of rats, which have undergone thyreoidectomy and parathyroidectomy and have been kept in the state of hypocalcemia, the bone salt dissolving function (which is noticed by the rise in the ionic concentration of the serum calcium) can be depressed by dosing acetylsalicylic acid. However, in said publication, it was not made clear how acetylsalicylic acid influenced the ossifying function of 1.alpha.-hydroxycholecalciferol. Because it has been known that in the bone tissues of the warm-blooded animals the bone salt dissolution and the ossification are carried out side by side simultaneously and it has been regarded that which of these mutually contradictory functions holds greater prominence is a matter of complication depending not only on the functions of the vitamin D.sub.3 derivative but also on the serum calcium ion, phosphorus, thyroid hormone, parathormone, calcitonin, corticosteroid, plostaglandin, etc.
The present inventors, based on the knowledge of said function peculiar to acetylsalicylic acid, continued the persistent efforts to develop the research and came to find that acetylsalicylic acid (or its pharmaceutically permissible salt) does not interfere with vitamin D.sub.3 or its derivative in its functions of absorbing calcium from the intestinal tract and of ossifying in the bone tissues and it favorably stimulates the ossifying function of vitamin D.sub.3 or its derivative not only in the warm-blooded animals subjected to hypocalcemia but also in the warm-blooded animal in normal condition.